Review: Pure Audio Reference and Control

A long time ago, in a galaxy far, far away, I bought a boatload of Plinius electronics. The reason? I wanted bass.

Like most things, it was a matter of timing and circumstance. My Merlin VSM-MXR loudspeakers and their carbon-splattered cones were absolutely the cat’s meow when it came to richness and midrange butter, but driven by tubes, the were not fast in the down-low, nor authoritative. At least, not with the tube amp I had on hand. Borrowing a Luxman L-590a II integrated, with its 30 watts of pure Class A power, opened my eyes. Out with the glass, in with the sand! Then, my dealer had this deal on some Plinius gear … the rest, they say, is history.

Fast forward five years and all of that gear is gone. Some of it, long gone. The whys and wherefores are tedious and trite and probably most helpfully cataloged as “I’m an audiophile”.

But the memories, they linger on.

What I was most impressed and astonished by, going over my mental card-catalog of character, started with something I tended to call “outstanding bass performance”. I went so far as to call my old Plinius SA-Reference “the best bass amp of all time”. I’ve been called out on this repeatedly since, but it wasn’t until I spent time with a $50k Soulution 530 integrated that my opinion wavered. The Plinius guys really were on to something. And sometimes, when the lights are low and the critters have all skittered off to bed, I wonder where that amplifier is now. Sniff.

But it’s not often, to be honest. I just don’t really have much need for an amp that much power. Is that blasphemy? It’s true, though — most of the speakers I have here are high-sensitivity players. I’ve learned that gobs of power are no replacement for quality.

Pure Audio

Pure Audio is a New Zealand brand founded by two Plinius ex-pats, designers Gary Morrison and Ross Stevens. Leveraging some of the ideas they’d been noodling on back at the Mothership, we now have a set of some truly remarkable electronics.

I first heard of Pure Audio at RMAF a few years back; last year, I had the good fortune to crash in the room next to the RMAF demo that importer Colleen Cardas Imports created around the line. CCI partner Marc Phillips (an occasional editorial contributor here at PTA, and the guy behind “The Smoking Jacket” series) walked me through the particulars, but more importantly, arranged to send the gear here for some quality time.

What I got was a pair of amplifiers, the Reference monoblocks, and a matching pre, the Control Preamplifier. I’ll confess — the names are nowhere near as interesting as the casework. So, lets start with that.

Looks and feels

The design is a little bit like something out of a Ridley Scott movie. You know. One where things pop out of people’s chests. I’m gonna put a pin in that and say that it’s probably going to be considered polarizing. I think it’s interesting to look at, the skeletal framework creates more of a cage than a chassis, and the inner metal mesh is enough to keep out unwary kiddie fingers and doggie tongues (don’t ask). Ventilation, to be sure, is dramatically better than your average box.

The cases are pretty much identical in size and shape, the obvious difference being the big knob on the front of the pre. That knob is outsized in the best way, and turning it through the 32 available steps is pure pleasure. The knob under your fingers may be the first clue to the unusual finish, especially if your lighting isn’t just so. If it is, you’ll know that the finish is very rough, sand-blasted, and the texture is very grippy under your fingers. It’s also sparkly, which is very cool, because it reminds me of everyone’s favorite vampires.

Turned to zero (or 6 o’clock on the dial), the pre is in standby; one click clockwise, and we’re one and ready to roll. That volume control is a slick relay-controlled network of Vishay-Dale resistors. It’s simple. It’s clean. It’s invisible. There is a remote, all run up in a warm wood sheath, but it’s “trim only” — you spin the knob on the pre to where you want it and then you can use the remote to dial it in a little bit to get it to taste, but massive swings (or a mute) means a walk to the rack.

The pre has a full set of inputs, including a tape loop, but it’s all single-ended. There’s also a mute switch. The other switch on the pre is the “light” — the little glowing white finger front-and-center on the face. Not sure why anyone would turn it off, but I guess you can. There’s also a trigger in/out — wiring a cable between the pre and the amps lets you send the amps into standby when you turn the volume down to zero. Not a bad thing when your amps are Class A and prone to suck juice as readily as a thirsty five-year-old.

Interestingly, there’s no source-selector. No knob. No switch. No series of buttons. In fact, there’s not a damn thing on the front of the unit, other than that honkin’ big knob. Selecting the active source is actually something of a magic trick. Internal circuitry “sees” the incoming signal and activates the appropriate signal path. That’s right! It’s automagic. Connect up four different sources, no problem. Fire up one, and the Control Preamplifier routes it. Kill it, start another, and the Control Preamplifier routes that new one. It never actually occurred to me to use two active sources at the same time, so I have no idea how an input duel will resolve. Try it, and lemme know!

The amps are, obviously, simpler than the Control Preamplifier. There’s the same toggle switch to turn on or off the skinny white finger on the face. There’s the same mute toggle, too. A single RCA input. A trigger input/output. And some big, black Cardas binding posts to taunt, mock and ridicule the banana connectors on your speaker cables. Here’s to hoping you have spades!

The amps have big heat-sinks, but they’re integral to the box, not hanging out on the outside like the old Plinius amps of yesterday. You can see the fins, though, all tucked under the skeleton on the font third of the amp. Heat sinks and Class A is usually what we call “a good start”, but it’s hardly the solution to round-the-calendar comfort, which is why the palm-sized fans tucked under them are so very interesting. I know — fans?!?! So much for my “sound floor” ….

But … so-called “silent fans” have been used in PC gaming cases for years, and there, they’re extraordinarily effective, even if their use in high-end audio has been anathema.

Here’s the picture: take a Class A amp, run it hard, bathe in the sound as you heat up your room and sweat your balls off. Here? Take a Reference Power Amplifier, a Class A amp, run it hard … and aside from the loving bit … nothing. Sure, the case gets warm. But the room? My nether regions? Comfy. The fan … works. And it’s silent from the seat. Score!

The only thing that troubles me about this casework, all skeletal and freaky-looking, is dust. Sure, the textured silver finish will hide many of the sins of a dusty room, no question. But I worry about serious dust. Mega Dust. Tuck these bad boys up into a rack and leave them there for a year or three and have fans gently whirling the floaties around and into the amp’s structure — thatkind of dust is gonna be hard to wipe off. I guess it’s a good thing the lids cage top is only held on with four hex nuts.

65 watts per channel isn’t a lot. You might even say it’s pretty meager. Yet and yet and yet … it’s enough. It’s more than enough. Let’s talk about that next.

Pairing

It’s a rare speaker that cannot be driven adequately with 65 watts. You might not get the swings you say you want, but unless you’re an unkind neighbor, partner, or parent, you’re almost never going to be “going there”, even if you could. Said another way, 80dB is still quite loud, especially if we’re talking about a quiet room in the first place. Given that your loudspeaker is going be to north of that as a baseline sensitivity, what you’re worrying about is drop off. What that translates into is a general requirement of 1-2 watts for most speakers at common listening distances. Sure, many speakers will need more juice to fill the same volume. Sure, some speakers need a lot more juice just due to the way they’re designed. Sure, more power on tap means more dynamic swings. Sure, more readily available power means harder hits. All that is true and more besides. But it’s also true that most speakers you listen to at common (less than 3m) will really not need anything like a mega amps output power. 100 watts, for most situations, is overkill. Unnecessary! And given that, if the output girth of a given amp means a subsequent drop in finesses, that’s a silly trade to make. Which brings me back to the 65 watts. It’s probably going to be enough. You may not be able to turn it up to rock concert levels, but then, rock concerts sound like crap so why is that a metric worth shooting for?

I rolled this pair through several different loudspeakers, starting with my personal reference, a pair of absurdly expensive Contriva Diacera SE loudspeakers from TIDAL. These speakers are full range, imposing, and about as well-turned out a piece of audio kit as I have ever seen. In a word, they’re breathtaking — both in looks and in sound. Overall, they’re very linear — unlike many designs, this pair has been engineered to produce a startlingly linear top-to-bottom coherence, and I can happily say that they’re way too much for my listening room.

My reference electronics, the ones I usually use with these speakers, are from Vitus Audio. These electronics are very refined and the sonic signatures match up very keenly to the big German speakers. Swapping in the set from Pure Audio was, in some ways, anti-climactic.

Compared preamp to preamp, the Pure Audio is quite a bit simpler. The remote control doesn’t really do a whole lot — “dialing in”, in this case, doesn’t mean much more than, say, 6dB of swing. Enough to tweak. But a mute would be really nice. Then there’s the whole no-button thing. The Vitus is quite a bit more complicated — it has an OS and a menus structure! But complexity is not always a good thing — here, I found that the Pure Audio pre was just as effective at doing it’s job. In fact, it was perhaps less visible to the signal chain. That was interesting. Especially at low-level listening. That was fascinating.

The amps, by contrast, were not invisible to the signal chain. That is not a bad thing. At all. There’s this thing that Class A amplifiers do that I quite cotton to — they warm things up, and not just the room they happen to sit in. There’s a fullness to the audio band that’s welcoming and delightful and almost entirely not solid-state-ish. The trick is to make that sound not cover up too much in the way of detail — warmth doesn’t have to entail smoothness, but the two tend to go hand in hand. Luxman, Marantz, I’m looking at you. But here, there is warmth and detail, though the Vitus gear did edge it out here.

With the big TIDAL speakers, the amps did truly excellent work. Compared to the Pass Labs XA100.5 mono amplifiers (which Mal reviewed here), the Pure Audio amps were simply more interesting. Bass seemed more solid without seeming artificial. “Royals” from Lorde’s Pure Heroine release from HDTracks, for example, did absolutely absurd things in my listening room — even when played low. I’m grinning now, listening to this track. It’s sick and may be entirely responsible for the over indulgence in italics. Hate to say it, but this may be the best I’ve heard out of these speakers. Hello, gorgeous.

On a grin, I swapped in a pair of Hørning Hybrid Eufrodite Ellipse loudspeakers. At 99dB, they’re not exactly the first loudspeakers I’d grab for a pair of solid-state power-amps, but the Plinius Hiss that I recalled from my time with the SA-Reference amplifiers was happily controlled. Turning up the tunes — I went right back to “Royals” — and my jaw dropped. I’ve never heard those speakers “do that” with bass. In fact, I’m pretty sure no one has heard those speakers go that low.

Sometimes, I love this job.

A final note — Class A operation is hell on my power bill. The Pure Audio gear has a neat feature that sends the amps into standby when the amps fail to see a signal for an extended period, or when volume on the pre is set to zero. For the latter, you just need to use the included remote trigger cables. The amps come on-song a bit faster from standby than from cold (they usually need at least a half-hour or so to hit stride) but when in standby, the power draw drops to a happy and cool 5 watts each. I love that.

Conclusion

The Pure Audio gear was “a happy surprise”.

I still fondly remember my time with my Plinius gear — and this gear from Pure Audio has clear roots in that history. And then it takes a giant step forward. The Control Preamplifier is one of the best I’ve heard — its only drawback, functionally, is that’s it’s single-ended only. The Reference monoblocks are killer and while they’re not as massive as the Plinius SA-Reference they seem to recall, that’s a fantastic thing and not a drawback.

Honestly, I don’t think anyone is going to have any issues at all with the Pure Audio pair — I know I don’t. At all. These are my favorite set of electronics to cross my system in years. They’re not perfect, but other than a higher output to handle speakers that are not as well-behaved as mine are, I can’t think of what I’d want changed. For me, these little fireballs are all-fun, all the time. Love love love.

I’ll confess that I’m not wild about the aesthetic. It’s very definitely an “acquired taste”, and while ultimately I think “striking” is probably a great thing for a brand, I do wonder if folks will take one look and, at the very least, scratch their head. Whatever your personal taste, Pure Audio can most definitely not be accused of being boring.

Balanced … that’s a preference thing. Some say balanced has a lower noise floor. Some say unbalanced has a bigger sound stage. I say “it depends on the implementation”. YMMV.

And FWIW, the Plinius SA-Reference amplifier is almost that, all by itself. Does that mean it’s bad? Or that’s it’s overpriced? Or that it’s out of line compared to its competitors? All good questions.

But I don’t think the gaps you’ve outlined are show-stoppers. Just things to be aware of.

I’d like to take the opportunity to elaborate on a couple of points. First, whenever I explain the Control’s automatic source selection to someone, their first question is usually, “What happens if I’m playing two sources at once?” I know, because I asked the same question, too! It’s relatively simple–the inputs are marked from 1 to 4, and they are prioritized that way. So if you’re playing something through Input 2, it will switch if you start playing something on Input 1…but not vice versa.

Secondly, Gary Morrison chose not to include balanced inputs because they generally require more complex circuitry in the amplifier. The idea behind PureAudio is to keep the design and the signal path as clean and simple as possible. That’s also why the remote only trims the volume–again, it’s less intrusive to the signal path.

Finally, all PureAudio products are available in black on request for no additional charge. If you think the PureAudio styling isn’t quite your thing, then you should see them in black–more conventional, but still very lovely to look at. In fact, I prefer the black, while Colleen loves the PureAudio in silver!